Linux Kernel up to 6.6.99/6.12.39/6.15.7 Genphy Driver rtnl_lock deadlock

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5.0	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.6.99/6.12.39/6.15.7. This affects the function rtnl_lock of the component Genphy Driver. The manipulation leads to deadlock. This vulnerability is referenced as CVE-2025-38537. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.99/6.12.39/6.15.7 and classified as critical. This issue affects the function rtnl_lock of the component Genphy Driver. The manipulation with an unknown input leads to a deadlock vulnerability. Using CWE to declare the problem leads to CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net: phy: Don't register LEDs for genphy If a PHY has no driver, the genphy driver is probed/removed directly in phy_attach/detach. If the PHY's ofnode has an "leds" subnode, then the LEDs will be (un)registered when probing/removing the genphy driver. This could occur if the leds are for a non-generic driver that isn't loaded for whatever reason. Synchronously removing the PHY device in phy_detach leads to the following deadlock: rtnl_lock() ndo_close() ... phy_detach() phy_remove() phy_leds_unregister() led_classdev_unregister() led_trigger_set() netdev_trigger_deactivate() unregister_netdevice_notifier() rtnl_lock() There is a corresponding deadlock on the open/register side of things (and that one is reported by lockdep), but it requires a race while this one is deterministic. Generic PHYs do not support LEDs anyway, so don't bother registering them.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-38537 since 04/16/2025. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 276629 (Ubuntu 24.04 LTS / 25.04 : Linux kernel vulnerabilities (USN-7879-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.100, 6.12.40 or 6.15.8 eliminates this vulnerability. Applying the patch ec158d05eaa91b2809cab65f8068290e3c05ebdd/fd6493533af9e5d73d0d42ff2a8ded978a701dc6/75e1b2079ef0653a2f7aa69be515d86b7faf1908/f0f2b992d8185a0366be951685e08643aae17d6d is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (276629) and CERT Bund (WID-SEC-2025-1858). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Dell Avamar
• Open Source Linux Kernel
• Dell NetWorker
• Dell Secure Connect Gateway
• IBM QRadar SIEM
• IBM Security Verify Access

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.6.17
• 6.6.18
• 6.6.19
• 6.6.20
• 6.6.21
• 6.6.22
• 6.6.23
• 6.6.24
• 6.6.25
• 6.6.26
• 6.6.27
• 6.6.28
• 6.6.29
• 6.6.30
• 6.6.31
• 6.6.32
• 6.6.33
• 6.6.34
• 6.6.35
• 6.6.36
• 6.6.37
• 6.6.38
• 6.6.39
• 6.6.40
• 6.6.41
• 6.6.42
• 6.6.43
• 6.6.44
• 6.6.45
• 6.6.46
• 6.6.47
• 6.6.48
• 6.6.49
• 6.6.50
• 6.6.51
• 6.6.52
• 6.6.53
• 6.6.54
• 6.6.55
• 6.6.56
• 6.6.57
• 6.6.58
• 6.6.59
• 6.6.60
• 6.6.61
• 6.6.62
• 6.6.63
• 6.6.64
• 6.6.65
• 6.6.66
• 6.6.67
• 6.6.68
• 6.6.69
• 6.6.70
• 6.6.71
• 6.6.72
• 6.6.73
• 6.6.74
• 6.6.75
• 6.6.76
• 6.6.77
• 6.6.78
• 6.6.79
• 6.6.80
• 6.6.81
• 6.6.82
• 6.6.83
• 6.6.84
• 6.6.85
• 6.6.86
• 6.6.87
• 6.6.88
• 6.6.89
• 6.6.90
• 6.6.91
• 6.6.92
• 6.6.93
• 6.6.94
• 6.6.95
• 6.6.96
• 6.6.97
• 6.6.98
• 6.6.99
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.15.0
• 6.15.1
• 6.15.2
• 6.15.3
• 6.15.4
• 6.15.5
• 6.15.6
• 6.15.7

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Deadlock
CWE: CWE-833 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 276629
Nessus Name: Ubuntu 24.04 LTS / 25.04 : Linux kernel vulnerabilities (USN-7879-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.100/6.12.40/6.15.8
Patch: ec158d05eaa91b2809cab65f8068290e3c05ebdd/fd6493533af9e5d73d0d42ff2a8ded978a701dc6/75e1b2079ef0653a2f7aa69be515d86b7faf1908/f0f2b992d8185a0366be951685e08643aae17d6d

Timelineinfo

04/16/2025 CVE reserved
08/16/2025 +122 days Advisory disclosed
08/16/2025 +0 days VulDB entry created
01/30/2026 +167 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38537 (🔒)
GCVE (CVE): GCVE-0-2025-38537
GCVE (VulDB): GCVE-100-320405
CERT Bund: WID-SEC-2025-1858 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 08/16/2025 18:04
Updated: 01/30/2026 18:52
Changes: 08/16/2025 18:04 (59), 09/28/2025 09:43 (7), 10/03/2025 14:32 (1), 10/12/2025 18:53 (1), 11/01/2025 19:49 (1), 11/19/2025 01:37 (12), 11/25/2025 03:26 (2), 01/30/2026 18:52 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion

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